Evaluation of different methods for the experimental infection of the land snail Helix aspersa with Aelurostrongylus abstrusus lungworm

The laboratory maintenance of parasitic life cycles is crucial to support research in many fields of parasitology.
The land snail Helix aspersa (syn. Cornu aspersum), an intermediate host of feline lungworms
Aelurostrongylus abstrusus and Troglostrongylus brevior, is adopted to produce infective stages of those
nematodes in laboratory condition. The aim of this study was to compare the most common methods of
experimental infection of H. aspersa with first stage larvae (L1) of A. abstrusus (i.e., contact of the snail
foot with the L1) with the injection of these larvae in the foot of the snail, instrumental to reduce the
infection time and to maximize the output of third-stage larvae (L3). Three groups (i.e., A, B, C) of 15
H. aspersa snails were infected with L1 of A. abstrusus (n = 250 for each snail), whereas a fourth group
(group D) was not infected (control). Snails were individually placed for 48 h on a microfilm containing
L1 (group A), on a potato slice previously irrigated with a suspension of L1 (group B), or they were
inoculated by injection of L1 in the posterior-ventral portion of the foot (group C). Eighteen days after
the infection all snails were analyzed and tissues were digested to recover L3. No difference in mortality
rate was recorded among snail groups and the mean number of retrieved L3 was significantly larger in
group C (71.5
±
52.9) compared to group B (38.2
±
44.9; p = 0.0161) and group A (19
±
23.3; p < 0.0001).
The injection of A. abstrusus L1 in the foot of H. aspersa proved to be a fast, easy to apply and effective
method, resulting in the largest number of infective larvae retrieved.